/* Geist fonts (DESIGN.md primary faces) */
@font-face {
  font-family: "Geist";
  src: url("https://cdn.jsdelivr.net/npm/geist@1.3.1/dist/fonts/geist-sans/Geist-Variable.woff2")
    format("woff2");
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Geist Mono";
  src: url("https://cdn.jsdelivr.net/npm/geist@1.3.1/dist/fonts/geist-mono/GeistMono-Variable.woff2")
    format("woff2");
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
}

/* Design tokens from DESIGN.md (Vercel-inspired) */
:root {
  --color-primary: #171717;
  --color-on-primary: #ffffff;
  --color-primary-hover: #000000;
  --color-ink: #171717;
  --color-body: #4d4d4d;
  --color-mute: #888888;
  --color-hairline: #ebebeb;
  --color-hairline-strong: #a1a1a1;
  --color-canvas: #ffffff;
  --color-canvas-soft: #fafafa;
  --color-canvas-soft-2: #f5f5f5;
  --color-link: #0070f3;
  --color-link-deep: #0761d1;
  --color-error: #ee0000;
  --color-success: #0070f3;
  --color-cyan: #50e3c2;
  --color-violet: #7928ca;
  --color-highlight-pink: #ff0080;
  --gradient-develop-start: #007cf0;
  --gradient-develop-end: #00dfd8;
  --gradient-preview-start: #7928ca;
  --gradient-preview-end: #ff0080;

  /* Editor pane — follows theme (light in light mode) */
  --color-editor-bg: #fafafa;
  --color-editor-fg: #171717;
  --color-editor-header: #ffffff;
  --color-editor-border: #ebebeb;
  --color-editor-mute: #888888;
  --color-editor-meta: #888888;
  --color-editor-scroll: #d4d4d4;
  --color-editor-scroll-hover: #a1a1a1;
  --color-editor-caret: #0070f3;
  --color-editor-selection-bg: rgba(0, 112, 243, 0.22);
  --color-editor-selection-fg: #171717;

  /* Fenced code blocks — stay dark for contrast in both themes */
  --color-code-bg: #171717;
  --color-code-fg: #f2f2f2;
  --color-code-border: #2e2e2e;

  --color-preview-scroll: #d4d4d4;
  --color-preview-scroll-hover: #a1a1a1;

  --font-sans: "Geist", "Inter", system-ui, -apple-system, sans-serif;
  --font-mono: "Geist Mono", ui-monospace, SFMono-Regular, Menlo, Monaco,
    monospace;
  /* Persian / Arabic UI face for RTL content */
  --font-rtl: "Vazirmatn", "Geist", "Tahoma", system-ui, sans-serif;

  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-pill: 100px;

  --space-xxs: 4px;
  --space-xs: 8px;
  --space-sm: 12px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-3xl: 48px;
  --space-4xl: 64px;

  --nav-height: 64px;
  --pane-header-height: 44px;
  --debounce-ms: 300ms;

  --shadow-level-2: 0px 1px 1px #00000005, 0px 2px 2px #0000000a,
    inset 0 0 0 1px #00000014;
  --shadow-level-4: 0px 2px 2px #0000000a, 0px 8px 16px -4px #0000000a,
    inset 0 0 0 1px #00000014;

  color-scheme: light;
}

/* Dark theme — canvas/ink + editor go dark; code blocks stay dark */
html[data-theme="dark"] {
  --color-primary: #ededed;
  --color-on-primary: #0a0a0a;
  --color-primary-hover: #ffffff;
  --color-ink: #ededed;
  --color-body: #a1a1a1;
  --color-mute: #666666;
  --color-hairline: #333333;
  --color-hairline-strong: #666666;
  --color-canvas: #0a0a0a;
  --color-canvas-soft: #111111;
  --color-canvas-soft-2: #171717;
  --color-link: #3291ff;
  --color-link-deep: #52a8ff;
  --color-error: #ff6161;
  --color-success: #3291ff;

  --color-editor-bg: #000000;
  --color-editor-fg: #f2f2f2;
  --color-editor-header: #0a0a0a;
  --color-editor-border: #262626;
  --color-editor-mute: #888888;
  --color-editor-meta: #666666;
  --color-editor-scroll: #3f3f3f;
  --color-editor-scroll-hover: #5a5a5a;
  --color-editor-caret: #50e3c2;
  --color-editor-selection-bg: rgba(0, 112, 243, 0.45);
  --color-editor-selection-fg: #ffffff;

  --color-code-bg: #000000;
  --color-code-fg: #f2f2f2;
  --color-code-border: #262626;

  --color-preview-scroll: #3f3f3f;
  --color-preview-scroll-hover: #5a5a5a;

  --shadow-level-2: 0px 1px 1px #00000040, 0px 2px 2px #00000040,
    inset 0 0 0 1px #ffffff14;
  --shadow-level-4: 0px 2px 2px #00000040, 0px 8px 16px -4px #00000060,
    inset 0 0 0 1px #ffffff14;

  color-scheme: dark;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  overflow: hidden; /* panes scroll internally; no page-level gutter */
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 400;
  line-height: 24px;
  color: var(--color-ink);
  background: var(--color-canvas);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

::selection {
  background: var(--color-primary);
  color: #f2f2f2;
}

/* Editor selection (tuned per theme via tokens) */
.pane-editor ::selection,
.editor::selection {
  background: var(--color-editor-selection-bg);
  color: var(--color-editor-selection-fg);
}

.pane-editor ::-moz-selection,
.editor::-moz-selection {
  background: var(--color-editor-selection-bg);
  color: var(--color-editor-selection-fg);
}

html[data-theme="dark"] ::selection {
  background: #ededed;
  color: #0a0a0a;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ─── App shell ─── */

.app {
  display: flex;
  flex-direction: column;
  width: 100%;
  height: 100%;
  min-height: 100dvh;
  overflow: hidden;
}

/* ─── Nav ─── */

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  height: var(--nav-height);
  min-height: var(--nav-height);
  padding: var(--space-sm) var(--space-lg);
  background: var(--color-canvas);
  border-bottom: 1px solid var(--color-hairline);
  z-index: 10;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  min-width: 0;
}

.nav-mark {
  width: 32px;
  height: 32px;
  flex-shrink: 0;
  display: block;
  border-radius: 5px;
  box-shadow: 0 0 0 1px #0000000a;
}

.nav-titles {
  min-width: 0;
}

.nav-title {
  margin: 0;
  font-size: 14px;
  font-weight: 500;
  line-height: 20px;
  letter-spacing: -0.28px;
  color: var(--color-ink);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.nav-subtitle {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 400;
  line-height: 16px;
  color: var(--color-mute);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  flex-shrink: 0;
}

.status {
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 16px;
  color: var(--color-mute);
  padding: 0 var(--space-xs);
  margin-right: var(--space-xxs);
  transition: color 0.15s ease;
}

.status.is-pending {
  color: var(--color-body);
}

.status.is-done {
  color: var(--color-success);
}

.status.is-error {
  color: var(--color-error);
}

/* ─── Buttons ─── */

.btn {
  appearance: none;
  border: none;
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 500;
  line-height: 20px;
  height: 32px;
  padding: 0 var(--space-sm);
  border-radius: var(--radius-pill);
  transition: background-color 0.12s ease, color 0.12s ease,
    box-shadow 0.12s ease, opacity 0.12s ease;
  white-space: nowrap;
}

.btn:focus-visible {
  outline: 2px solid var(--color-link);
  outline-offset: 2px;
}

.btn:active {
  transform: translateY(0.5px);
}

.btn-primary {
  background: var(--color-primary);
  color: var(--color-on-primary);
}

.btn-primary:hover {
  background: var(--color-primary-hover);
}

.btn-secondary {
  background: var(--color-canvas);
  color: var(--color-ink);
  box-shadow: inset 0 0 0 1px var(--color-hairline);
}

.btn-secondary:hover {
  background: var(--color-canvas-soft);
}

/* Download dropdown */
.download-menu {
  position: relative;
  display: inline-flex;
}

#btn-download {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding-inline-end: 8px;
}

#btn-download .icon-chevron {
  width: 14px;
  height: 14px;
  flex-shrink: 0;
  opacity: 0.7;
  transition: transform 0.15s ease;
}

#btn-download[aria-expanded="true"] .icon-chevron {
  transform: rotate(180deg);
}

.download-menu-list {
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  z-index: 40;
  min-width: 180px;
  padding: 4px;
  background: var(--color-canvas);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-level-4);
  border: 1px solid var(--color-hairline);
}

.download-menu-list[hidden] {
  display: none;
}

.download-menu-item {
  appearance: none;
  display: block;
  width: 100%;
  margin: 0;
  padding: 8px 12px;
  border: none;
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--color-ink);
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 500;
  line-height: 20px;
  text-align: start;
  cursor: pointer;
  transition: background-color 0.12s ease;
}

.download-menu-item:hover,
.download-menu-item:focus-visible {
  background: var(--color-canvas-soft-2);
  outline: none;
}

.download-menu-item:active {
  background: var(--color-canvas-soft);
}

/* Icon toggle (theme) */
.btn-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  padding: 0;
  background: var(--color-canvas);
  color: var(--color-ink);
  box-shadow: inset 0 0 0 1px var(--color-hairline);
}

.btn-icon:hover {
  background: var(--color-canvas-soft);
}

.btn-icon .icon {
  width: 16px;
  height: 16px;
  display: block;
  flex-shrink: 0;
}

/* Show sun in dark mode (click → light), moon in light mode (click → dark) */
.btn-icon .icon-sun {
  display: none;
}

html[data-theme="dark"] .btn-icon .icon-sun {
  display: block;
}

html[data-theme="dark"] .btn-icon .icon-moon {
  display: none;
}

/* ─── Split panes ─── */

.panes {
  display: grid;
  grid-template-columns: 1fr 1fr;
  flex: 1 1 auto;
  width: 100%;
  min-height: 0;
  min-width: 0;
  overflow: hidden;
}

.pane {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
}

.pane-editor {
  background: var(--color-editor-bg);
  color: var(--color-editor-fg);
  border-right: 1px solid var(--color-editor-border);
}

.pane-preview {
  background: var(--color-canvas);
}

.pane-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--pane-header-height);
  min-height: var(--pane-header-height);
  padding: 0 var(--space-lg);
  border-bottom: 1px solid var(--color-editor-border);
  background: var(--color-editor-header);
}

.pane-header-preview {
  background: var(--color-canvas);
  border-bottom: 1px solid var(--color-hairline);
}

.pane-label {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 400;
  line-height: 16px;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  color: var(--color-editor-mute);
}

.pane-header-preview .pane-label {
  color: var(--color-mute);
}

.pane-meta {
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 16px;
  color: var(--color-editor-meta);
}

.pane-header-preview .pane-meta {
  color: var(--color-mute);
}

/* ─── Editor ─── */

.editor {
  flex: 1;
  width: 100%;
  min-height: 0;
  margin: 0;
  padding: var(--space-lg);
  border: none;
  resize: none;
  outline: none;
  background: transparent;
  color: var(--color-editor-fg);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 400;
  line-height: 20px;
  letter-spacing: 0;
  caret-color: var(--color-editor-caret);
  tab-size: 2;
  direction: ltr;
  text-align: start;
  /* thin custom scrollbar (Firefox) */
  scrollbar-width: thin;
  scrollbar-color: var(--color-editor-scroll) transparent;
}

.editor.is-rtl,
.pane-editor.is-rtl .editor {
  direction: rtl;
  font-family: var(--font-rtl);
  font-size: 15px;
  line-height: 26px;
  letter-spacing: 0;
  /* Slightly taller line-height suits Persian/Arabic script */
}

.editor::placeholder {
  color: var(--color-editor-meta);
}

.editor:focus {
  outline: none;
}

/* ─── Custom scrollbars (editor + preview) ─── */

.editor::-webkit-scrollbar,
.preview::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

.editor::-webkit-scrollbar-track,
.preview::-webkit-scrollbar-track {
  background: transparent;
}

.editor::-webkit-scrollbar-thumb {
  background-color: var(--color-editor-scroll);
  border-radius: 100px;
  border: 2px solid transparent;
  background-clip: content-box;
}

.editor::-webkit-scrollbar-thumb:hover {
  background-color: var(--color-editor-scroll-hover);
  border: 2px solid transparent;
  background-clip: content-box;
}

.editor::-webkit-scrollbar-corner {
  background: transparent;
}

.preview::-webkit-scrollbar-thumb {
  background-color: var(--color-preview-scroll);
  border-radius: 100px;
  border: 2px solid transparent;
  background-clip: content-box;
}

.preview::-webkit-scrollbar-thumb:hover {
  background-color: var(--color-preview-scroll-hover);
  border: 2px solid transparent;
  background-clip: content-box;
}

.preview::-webkit-scrollbar-corner {
  background: transparent;
}

/* ─── Preview surface ─── */

.preview {
  flex: 1;
  width: 100%;
  min-width: 0;
  min-height: 0;
  overflow-x: hidden;
  overflow-y: auto;
  padding: var(--space-xl) var(--space-xl) var(--space-4xl);
  scroll-behavior: smooth;
  background: var(--color-canvas);
  /* thin custom scrollbar (Firefox) */
  scrollbar-width: thin;
  scrollbar-color: var(--color-preview-scroll) transparent;
}

.preview:focus-visible {
  outline: 2px solid var(--color-link);
  outline-offset: -2px;
}

.empty-state {
  max-width: 420px;
  margin: 12vh auto 0;
  text-align: center;
  padding: var(--space-3xl) var(--space-lg);
  background: var(--color-canvas-soft);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-level-2);
}

.empty-title {
  margin: 0 0 var(--space-xs);
  font-size: 20px;
  font-weight: 600;
  line-height: 28px;
  letter-spacing: -0.6px;
  color: var(--color-ink);
}

.empty-body {
  margin: 0;
  font-size: 14px;
  font-weight: 400;
  line-height: 20px;
  letter-spacing: -0.28px;
  color: var(--color-body);
}

/* ─── Prose (beautiful Markdown result) ─── */

.prose {
  width: 100%;
  max-width: none;
  color: var(--color-ink);
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 400;
  line-height: 28px;
  text-align: start;
}

/* RTL preview: Vazirmatn + RTL direction */
.prose.is-rtl,
.prose.is-rtl .prose-content,
.pane-preview.is-rtl .prose {
  font-family: var(--font-rtl);
  direction: rtl;
  text-align: start;
  line-height: 1.9;
}

.prose-content {
  width: 100%;
  transition: opacity 0.18s ease;
}

.prose > :first-child,
.prose-content > :first-child {
  margin-top: 0;
}

.prose > :last-child,
.prose-content > :last-child {
  margin-bottom: 0;
}

.prose h1,
.prose h2,
.prose h3,
.prose h4,
.prose h5,
.prose h6 {
  color: var(--color-ink);
  font-weight: 600;
  letter-spacing: -0.02em;
  margin: 1.6em 0 0.5em;
  line-height: 1.25;
  text-align: start;
}

.prose.is-rtl h1,
.prose.is-rtl h2,
.prose.is-rtl h3,
.prose.is-rtl h4,
.prose.is-rtl h5,
.prose.is-rtl h6 {
  font-family: var(--font-rtl);
  letter-spacing: 0;
  line-height: 1.45;
}

.prose h1 {
  font-size: 32px;
  line-height: 40px;
  letter-spacing: -1.28px;
  margin-top: 0;
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--color-hairline);
}

.prose.is-rtl h1 {
  letter-spacing: 0;
  line-height: 1.4;
}

.prose h2 {
  font-size: 24px;
  line-height: 32px;
  letter-spacing: -0.96px;
  padding-bottom: var(--space-xs);
  border-bottom: 1px solid var(--color-hairline);
}

.prose.is-rtl h2 {
  letter-spacing: 0;
  line-height: 1.45;
}

.prose h3 {
  font-size: 20px;
  line-height: 28px;
  letter-spacing: -0.6px;
}

.prose.is-rtl h3 {
  letter-spacing: 0;
}

.prose h4 {
  font-size: 16px;
  line-height: 24px;
  font-weight: 500;
  letter-spacing: -0.28px;
}

.prose.is-rtl h4 {
  letter-spacing: 0;
}

.prose p {
  margin: 0 0 1em;
  color: var(--color-body);
}

.prose strong {
  color: var(--color-ink);
  font-weight: 500;
}

.prose em {
  font-style: italic;
}

.prose a {
  color: var(--color-link);
  text-decoration: underline;
  text-underline-offset: 2px;
  text-decoration-thickness: 1px;
}

.prose a:hover {
  color: var(--color-link-deep);
}

.prose ul,
.prose ol {
  margin: 0 0 1em;
  padding-inline-start: 1.4em;
  padding-inline-end: 0;
  color: var(--color-body);
}

.prose li {
  margin: 0.3em 0;
}

.prose li::marker {
  color: var(--color-mute);
}

.prose li > ul,
.prose li > ol {
  margin: 0.3em 0;
}

.prose blockquote {
  margin: 0 0 1em;
  padding: var(--space-sm) var(--space-md);
  border-inline-start: 3px solid var(--color-primary);
  border-inline-end: none;
  background: var(--color-canvas-soft);
  border-start-start-radius: 0;
  border-start-end-radius: var(--radius-sm);
  border-end-end-radius: var(--radius-sm);
  border-end-start-radius: 0;
  color: var(--color-body);
}

.prose blockquote p:last-child {
  margin-bottom: 0;
}

.prose hr {
  border: none;
  height: 1px;
  background: var(--color-hairline);
  margin: var(--space-xl) 0;
}

.prose code {
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 20px;
  background: var(--color-canvas-soft-2);
  color: var(--color-ink);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  border: 1px solid var(--color-hairline);
  /* Inline code is LTR even in RTL prose */
  direction: ltr;
  unicode-bidi: isolate;
  display: inline-block;
}

.prose pre {
  margin: 0 0 1.25em;
  padding: var(--space-lg);
  background: var(--color-code-bg);
  color: var(--color-code-fg);
  border-radius: var(--radius-md);
  overflow-x: auto;
  box-shadow: var(--shadow-level-4);
  border: 1px solid var(--color-code-border);
  /* Fenced code always LTR */
  direction: ltr;
  text-align: left;
  unicode-bidi: isolate;
}

.prose pre code {
  display: block;
  padding: 0;
  background: transparent;
  border: none;
  color: inherit;
  font-size: 13px;
  line-height: 20px;
  white-space: pre;
  direction: ltr;
}

.prose table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin: 0 0 1.25em;
  font-size: 14px;
  line-height: 20px;
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-md);
  background: var(--color-canvas);
  box-shadow: var(--shadow-level-2);
  overflow: hidden;
}

.prose th,
.prose td {
  text-align: start;
  padding: 10px var(--space-sm);
  border-bottom: 1px solid var(--color-hairline);
  border-inline-end: 1px solid var(--color-hairline);
  color: var(--color-body);
  vertical-align: top;
}

.prose th:last-child,
.prose td:last-child {
  border-inline-end: none;
}

.prose th {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 400;
  line-height: 16px;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  color: var(--color-mute);
  background: var(--color-canvas-soft);
}

.prose.is-rtl th {
  font-family: var(--font-rtl);
  text-transform: none;
  letter-spacing: 0;
  font-weight: 500;
}

/* Zebra striping for body rows — clearer scanning */
.prose tbody tr:nth-child(even) td {
  background: var(--color-canvas-soft);
}

.prose tbody tr:hover td {
  background: var(--color-canvas-soft-2);
}

/* No double line under last row; round outer corners */
.prose tr:last-child th,
.prose tr:last-child td {
  border-bottom: none;
}

.prose tr:first-child th:first-child,
.prose tr:first-child td:first-child {
  border-start-start-radius: var(--radius-md);
}

.prose tr:first-child th:last-child,
.prose tr:first-child td:last-child {
  border-start-end-radius: var(--radius-md);
}

.prose tr:last-child th:first-child,
.prose tr:last-child td:first-child {
  border-end-start-radius: var(--radius-md);
}

.prose tr:last-child th:last-child,
.prose tr:last-child td:last-child {
  border-end-end-radius: var(--radius-md);
}

.prose img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-level-2);
  margin: 0.5em 0 1em;
}

.prose input[type="checkbox"] {
  margin-inline-end: var(--space-xs);
  margin-inline-start: 0;
  accent-color: var(--color-primary);
}

/* Soft fade when content updates */
.preview.is-updating .prose-content {
  opacity: 0.55;
}

/* ─── Responsive ─── */

@media (max-width: 800px) {
  .nav {
    flex-direction: column;
    align-items: stretch;
    height: auto;
    min-height: var(--nav-height);
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-md);
  }

  .nav-actions {
    flex-wrap: wrap;
    justify-content: flex-end;
  }

  .status {
    width: 100%;
    margin: 0 0 var(--space-xxs);
    order: -1;
  }

  .panes {
    grid-template-columns: 1fr;
    grid-template-rows: minmax(40vh, 1fr) minmax(50vh, 1fr);
  }

  .pane-editor {
    border-right: none;
    border-bottom: 1px solid var(--color-editor-border);
  }

  .preview {
    padding: var(--space-lg);
  }

  .btn-primary span,
  .btn {
    font-size: 13px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }

  .preview {
    scroll-behavior: auto;
  }
}